Linear accelerators can be used for radiation treatment in the medical field and can include targeting systems using x-ray machines, for example. Linear accelerators have a limited life span and are expensive. For example, an x-ray tube in a linear accelerator may have a warranty usage of some predetermined number of uses. Thereafter, the owner of the machine usually needs to either replace the x-ray tube or service the x-ray tube to extend the useful lifespan of the machine. Frequently, the cost to service the machine is significantly less than the cost of replacing an x-ray tube or an entire linear accelerator. Therefore, it is desirable to have systems and methods of servicing and maintaining a linear accelerator that be used as an alternative to replacing a linear accelerator.
FIG. 1 is a diagrammatic illustration of an exemplary radiation generating machine 10. The machine 10 includes a base support 12, a moveable gantry 14, and a linear accelerator 16 carried within the gantry 14. The linear accelerator 16 includes an x-ray tube 18, which may be carried in an arm of the gantry 14, and a cooling system 20 for cooling the x-ray tube 18 during use. The cooling system 20 includes a heat exchanger 22, coolant circulation conduits 24 that connect the heat exchanger 22 to the x-ray tube 18, and usually additional equipment, such as pumps, valves, and/or switches to control the flow and circulation of coolant between the heat exchanger 22 and the x-ray tube 18.
The x-ray tube 18 generates significant amounts of heat during its use. The generated heat, however, can damage the working parts of the x-ray tube 18. Therefore, the cooling system 20 is used to cool the x-ray tube 18 and thereby prevent premature failure of the working parts of the x-ray tube 18.
The cooling system 20 operates by circulating a coolant, usually oil, such as Shell Diala AX, through the x-ray tube 18 and to the heat exchanger 22. The heat exchanger 22 cools the coolant and then the coolant is returned to the x-ray tube 18 through the circulation conduits 24, where the cooling process is repeated. However, the coolant breaks down over time due to the heat generated by the x-ray tube, which diminishes the ability of the coolant to function at its optimal performance levels. When this happens, either the entire x-ray tube 18 must be replaced or the old coolant can be replaced with new coolant.
As indicated above, it is generally significantly less expensive to replace the coolant rather than buying an entirely new x-ray tube 18. However, there are some limitations that must be met. One significant limitation is that the coolant should not have any air entrapped therein. Entrapped air in the coolant can degrade the coolant in the x-ray tube 18. Therefore, in replacing the coolant, it is important to minimize or eliminate any entrained air in the coolant. To this end, the cooling system 20 of the linear accelerator 16 is a closed system, which is sealed to prevent air from entering into the cooling system and the coolant.